Drill



UIRHE DRILL,

No. 439,972. Pat ented Nov. 4, 1890.

A T T (In/15y.

UNITED STATES PATENT OFFICE.

.JOHN MUIRI-IEAD, OF PITTSTON, PENNSYLVANIA.

DRILL.

SPECIFICATION forming part of Letters Patent No. 439,972, dated November 4, 1890.

Application filed June 10, 1890. Serial No. 354,904. (No model.)

To all whom it may concern:

Be it known that I, JOHN MUIRHEAD, a citizen of the United States, residing atPittston, in the county of Luzerne and State of Pennsylvania, have invented a new and useful Improvement in Drills, which improvement is fully set forth in the following specification and accompanying drawings.

My invention relates to improvements in drills; and itconsists, first, of a drill having a stem with enlarged portions, the latter having a tapering opening, and a groove leading thereinto, in combination with a bit adapted to be held in said opening and groove; second, of a drill having a screw threaded portion of its stem provided with a movable guide-block, the latter being held in place by a key, substantially as described.

Figure 1 represents a side view of a drill having a tool-holder with bits and a guidingblock as embodying my invention. Fig. 2 represents a central longitudinal sectional view of the device shown in Fig. 1. Figs. 3 and 4 represent cross-sections on lines x w and y y, respectively, Fig. 1. Fig. 5 represents a perspective view of one of the bits.

Similar letters of reference indicate corresponding parts in the several figures.

Referring to the drawings, A designates a drill consisting of the holder B, the stem portion G, the guiding-block D, and the bits E.

The holder B is formed of the enlarged portions F and G of the stem, the larger portion F having a series of conical or tapering openings H therein at equal distances from the center of the stem, and the smaller portion G having the grooves J, the said openings and grooves extending in the same direction and being adapted to receive, respectively, the tapering necks K and the back portions L of the bits E. The shouldered portions M of the bits are in contact with one side of the said larger portion F, and on the screwthreaded ends K of the necks K are the clamping-nuts N, which bear against the holder B and reliably retain the bits in place therein.

The bits E have enlarged or widened front or outer portions P, and the beveled faces of their cutting-edges are the widest at the outer edge of the bit, as at Q, the said cutting-edges extending beyond the periphery of the holder.

The upper end of the stem 0 is provided with the usual head R and a screw-thread S for securing the drill to its operating mechanism.

The lower end of the stem has a screwthreaded portion T, on which is secured the many-sided guiding-blocksD by means of the key U, which latter is seated in the slot V of the stem, and the recess or groove X of the said block D.

When it is desired to place a bit in the holder, the tapering neck K is inserted in an opening H, the back of the bit being in the adjacent groove J, and .the bit is pushed so that the threaded portion K of the neck K projects from the holder, when a nut N is secured thereon so as to clamp said bit in proper position. In releasing the bit the nut is first removed from the neck, and the bit is pushed outward in the line of the groove so as to remove the neck from the opening and thereby permit its release from the holder.

In operating the device the end of the stem having the guiding-block D is first inserted in a small opening suitably formed in the article to be drilled, so that the said blockD may serve as a guide for the drill in its reciprocating as well as rotary motion.

It will be seen that with bits formed and secured as herein described a hole or opening of uniform diameter may readily be drilled in any suitable material, the said hole also having its walls extending in the same direction.

Owing to the front or outer portion of the bit being the widest, the extra wear and greater strain which are at the outer part of the cutting-edge are provided for.

Having thus described my invention, What I claim as new, and desire to secure by Letters Patent, is-

1. A drill havinga stem with enlarged portions forming a tool-holder, one of said portions being provided with a tapering opening and another with a-groove leading from said opening, in combination with a bit having a tapering neck adapted to fit in said opening and a back adapted to fit in said groove, substantially as and for the purpose set forth.

2. A drill having a stem with enlarged portions forming a tool-holder, one of said por tions being provided with a tapering opening and another with a groove leading from said opening, in combination with a bit having a thickened front or outer portion and a 5 tapering neck or shank forming a shoulder with said outer portion, thereby providing a cutting-edge of greater Width than the said neck or shank, substantially as described.

3. A drill having on its stem a screw-threaded portion at or near one end thereof, a mov- I: able block on said screw-threaded portion of the stem, and a key seated in a slot in said stenrand in a recess in said block, substantiallyas described. 7

' JOHN MUIRHEAD.

Witnesses:

ROBERT DICKSON,

S. P. FENN. 

